Signal system with continuous rail connections.



1). J MQOARTHY.

SIGNAL SYSTEM WITH CONTINUOUS RAIL CONNECTIONS. APPLICATION FILED APB. 25.1907.

907, 1 65 Patented Dec. 22, 1908.

' n'mfsss Irv/2 2 I 3L UNITED STATES -PATEN T OFFICE.

DANIEL J. McCARTHY, OF WILKINSBURG, PENNSYLVANIA, ASSIGNORTO UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

. Specification of Letters Patent.

Patented Dec. 22, 1908.

Application filed April 25, 1907. .Serial No. 370,230.

To all whom it may concern: I Be it known that I, DANIEL J MCCARTHY,

of Wilkinsburg, Allegheny county, Pennsylvania, have. invented a new and useful Signal System with Continuous Rail Connections, of which the following is a full, clear, and exact description,reference being had'to the accompanying drawings, forming'part of this specification,- in which the figure is a diagrammatic plan view showing a portion of a railway-track constructed in accordance with my invention.

The invention relates to block signaling, and is designed to do away with the use of insulated joints and impedance bonds. In my system the rails are in continuous electric connection with each other, and the impedance of the rails is utilized by connecting transformers to successive portions of the track, two transformers being used with one relay to operate a signal protecting a certain portion of the track.

In the drawings, 2 hating current generator supplying current to the line which energizes transformers 4, 5 and 6. The secondaries of these transformers are connected to the track rails 7 and 8, to which are connected the relays 9, ll), etc. These relays are connected to the rails at points about midway between the transformer connections; and the voltage of the secondaries of the transformers is made such that the combined action of two transformers, such as 5 and 6 is of the proper value for furnishing the necessary amount of current to-relay 10 for its operation.

' a danger condition.

If the rails are short circuited by a train at any point between 4 and 5, the relay 9 will be shunted, thus opening the local circuit 11 to signal 12, causing it to indicate As the train passes from between transformers 4 and 5 to the represents an alter- The advantages of my invention result from doing away with the track sections with insulating joints-and impedance coils; by impressing currents upon successive portions of the track, and using two transformers to operate a relay controlling the signal which protects such portion. The system is simple and not liable to get out of order, and only one frequency of current need be employed. I

The system may be employed for electric roads using either direct current or alternating current, the alternating current being of a different frequency from that for the signal system ;'or the system may be applied to steam roads or roads having other power for propulsion.

Other variations may be made in the form and arrangement of the device and their connections without departing from my invention.

I claim 1. A-railroadhaving the-rails in continuous electric connection, a signal system having signals each connected to one relay only,

and two transformers each of the same phase one relay only, and two transformers supplying currents of the same frequency in the same phaseto said relay, each ofthe transformers supplying an insufficient current to operate said relay substantially as described.

3. A railroad having the rails in continuous electrical connection, a signal system having signals each connected to one relay only, and two transformers each of which is arranged to supply current through the track rails to said relay either one of said transformers alone supplying insullicient current to operate the relay, substantially as described. 1 a

4. A railroad having the rails in continuous electrical connection, a signal system having signals each connected to one relay to operate the relay, and each transformer only, and two transformers each of which is In testimony whereof, I have hereunto set arranged to supply current through the track my hand. rails to said relay, either one of said transformers alone supplying insufficient current DANIEL JYMOOARTHY' Witnesses: I

supplying current to relays controlling two JOHN D. TAYLOR, different signals; substantially as described.

ELMER R. 00E. 

